Fallout New Vegas Weight Gain Mod

I had an idea for how to get a weight gain mod to work for Fallout New Vegas.

While I was goofing off during my break from the CK2 mod I’ve been making, I got in the mood to play New Vegas again. While I was looking for mods to install, I noticed that someone made the bodyslide and outfit studio mod work for New Vegas, allowing CBBE bodies to be used. While it’s not like the Fallout 4 or Skyrim bodyslides that allowed for the changes happen mid game, it does still allow the creation of other body types (including fat bodies). It only included a few outfits, but the potential to convert all vanilla clothing exists now.

So I opened the GECK to see if I could make a simple weight gain and loss system. I have almost no experience with the GECK, however I pretty much already have the base system finished. Here’s what I’ve got so far after about a day’s worth of work:

  1. 5 stages of weight gain (6 if you count being normal weight)
  2. A perk for each level of weight, all with buffs (DR) and debuffs (speed and agility)
  3. Weight loss that happens at the beginning of every day.
  4. five effects that can be placed on food that facilitate the weight gain (the effects are five tiers of how much weight is gained from eating the food item)
  5. A trait that can be chosen at the start of the game that increases how much weight is gained as well as increasing the amount of HP is restored from edible food.
  6. Experimental script (for me anyway) that replaces a specific manhole/hatch when at max weight level to simulate the character not being able to go through it (A message will pop up describing the scene if you try to go through it).

I also tried with the original .esp file to add more dialogue options to vanilla NPCs related to your current fat level and the appetite trait. This turned out to be a disaster because of how I directly edited vanilla quests in the editor (which can cause incompatibility issues). I would need to learn the other ways of adding dialogue before I can do this.

The last piece of the puzzle is the visual aspect of weight gain. While I didn’t attempt anything related to this, I know a way to do it because of a different mod. What I would need to do is make 5 versions of every female body armor/clothing to fit the weight levels and make a script that will auto switch these outfits around when weight is gained. Sexout Pregnancy already has a script that does pretty much the same thing, so if I reverse engineer it to make something similar, the weight gain mod would be able to have visual weight gain.

if anyone wants the prototype .esp file, I’ll upload it here.

For those that are curious about the specifics about how the system works, I’ll go into detail here.

The weight gain system will not start until you eat your first time capable of causing weight gain.

I use two variables to track the system one for weight level, and another to track progress towards next level (we’ll call them weight points). Every 100 weight points, you gain 1 weight level. When you go up in weight level, your weight points will go back to 0. If your weight points are ever less then 0, you will go down in weight level and your current weight points will be set to 95 (not perfect I know, but this way is more stable and less prone to bugs).

Every day you will lose -5 weight points (though I will likely change this to be based on endurance and strength)

The weight gain categories for food are
“None” (things like water, and fresh apples)
low +1 weight points (leaner meats like mantis)
Medium +2 weight points (things like gecko)
High +3 weight points = (alcohol, most prewar foods, brahmin steak)
Very high +4 weight points = (Sweets mostly)
Extreme +5 weight points = (Very few misc. things like Wasteland Omelets, Ant Queen Pheremones,
any glowing variants of NukaCola or Atomic Cocktails)

The weight level perks go like this (these are not accumulative):
Well fed: DR (not DT) +2, movement speed -2%
Chubby: DR +4, movement speed -5%
Fat: DR +6, movement speed -10%, Agility -1
Obese: DR +8, movement speed -15%, Agility -2
Morbidly Obese: DR +10, movement speed -20%, Agility -3

The Big Appetite trait: increases edible food’s (things like cooked food or prewar stuff) health restoration and weight gain (for low, med, and high weight gain foods this trait adds +1 weight. Very High increases by +2 and extreme is increased by +3). Prewar foods also receive greater health restoration.


Ah, New Vegas, even tho it’s one of my favorite games I’d still try this mod.

For the outfits and bodies I think you can do it by using the famous bodyslide, I think it works with F3 and NV too.

I’ll still wait 'til it’s visual !

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I’m not skilled in modding, but I fully support your efforts in making this mod it sounds amazing! And good job on creating something already that’s pretty impressive :smiley:


Here’s some examples of what it could be like with visuals. I played around with the sliders on one of the outfits that are already converted. This isn’t in the actual prototype mod, I just made the build for the outfit, launched the game took a screenshot, and repeated this 5 times. Note that it would need some touching up due to clipping, since the outfits were probably not intended to be stretched this much:

Well Fed:




Morbidly Obese:

Morbid Obese Side View:


One thing you could do is maybe track down a modder who’s skilled in editing Fallout New Vegas bodies? Easier said than done I know but I imagine that if you could delegate that chunk of the work to someone it would mean you could focus on the weight gain system.

And you may be able to find a modder who’s capable of splicing voices like in a few Fallout 4 mods I’ve seen to create the various weight level dialogue. Again, easier said than done but there might be volunteers out there


I think for the most part finding someone able to make the edits would come down to if they are familiar with bodyslide for Skyrim/Fallout 4 or not. The real problem is it would probably have to be someone from here. I doubt there would be many non fetishists willing to take on such a large project for something they probably wouldn’t enjoy. I’m hoping to find a volunteer for this, but if I can’t I’ll just have to add that to the list of skills I’ve learned for making fetish mods once the CK2 mod is done.

As for the dialouge, I’d be comfortable with silent voices when necessary. Even though New Vegas used to hold world record for most lines of recorded dialogue in a video game, I don’t think there is enough present to make fat fetish dialogue without it sounding like a YTP. My main hurdle is editing vanilla dialogue choices without causing mass incompatibility.


OH man this would be absolutely fucking Rad to see made (wish I could help but alas I’m not a modder)
edit: pun slightly intended


There are two ways I could see having the outfits fit the character. I’m not so sure which one I would prefer over the other.

  1. The unimmersive way: This is simply just having the armors automatically stretch and fit the character as they gain and lose weight. The benefit of this is the convenience provided to the player. The downside is the missed opportunities for some added depth to the system, and it’s more difficult to do on a wide scale. I would need to always have this option for the nude outfits so it would have to present to some degree anyway.

  2. The “immersive” way: This method would have your character’s armor unequiped if you are not in the correct weight level for the armor. I would make it so you can take your armor to a workbench to refit it to your desired size. The “recipes” for the refitting armor would only appear if you have the specific armor in your inventory (to avoid cluttering the menu with 5 versions of every body armor in the game). I would make it cost a resource to refit the armor, probably using scrap metal for metal based armors, leather (new recipe made from hides), and cloth (new item I’d have to add to stores) to make the refits. Benefits are this method is much easier to make and it can provide some panic scenarios if you can’t fit in your armor in the middle of a fight or if you can’t refit your armor. Downsides is that this could be found to be annoying for some players and it makes survival a less viable healing method for any character not already at the highest weight level (which I suppose could be a positive because of how medicine is kind of a meh skill on hardcore mode, this would even it out a bit).


Personally I think the “UnImmersive” choice is the better of the two. Although a compromise that you may be able to do is instead of the clothing becoming unwearable if your character jumps up a size, the clothes instead just receive condition damage


@Skinny_Guy It’s more the difficulty that will be the deciding factor of which I go with, since I really don’t have much experience with the GECK. I will probably leave it up to a poll if I can do the Unimersive on a wider scale. Thank you for voicing your preference :slightly_smiling_face:

A few things I changed:
First I adjusted the weight points needed to gain a weight level to 75 (100 was too many and 50 was way too little).

Changed the weight loss calculation. It has a lower base weight loss than before, but the higher your strength and endurance the more you lose daily (Endurance does more than strength). The fast metabolism trait also helps speed up weight loss.

Added a broken visual weight gain system. It only applies for nude characters, and it currently prevents any armor being worn if you are not at the normal weight level, but the base for the later visual system is there.

Adding one dialogue route to an existing quest that doesn’t need to be directly edited (During the good route of “Beyond the Beef” I’m making an option to make it easier to obtain Philippe’s recipes and get him locked in the pantry based on weight level and lower speech check of 30 vs. the normal 55).


This would be amazing.
Sadly, New Vegas Modding has slowed down. There are still great mods being made for it, but it’s usually limited to guns or outfits. This sounds great!

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Slowed down ? Maybe a bit, but not that much, just look at Simply Uncut.

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I stand corrected.
I mean more on the NSFW side of things, but holy shit this is awesome.
I’m gonna need to download this badboy asap.

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I’m not sure how different body modding is between FO4 and New Vegas is but you may be able to see if anyone is willing to help from the Fallout 4 Vore mod discord. While the mod is primarily vore focused, there is a very well made weight gain system built into it that allows you to somewhat customize how the character looks at higher weights. There is also Coldsteelj on deviantart that has his own weight gain mod for FO4 but they mostly work for commission.

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Philippe’s new dialogue options are done. I wanted to have a demonstration of what I can do when it comes to quest design. So here’s what I made (this has some minor spoilers for a 10 year old game):

Philippe is the head chef of the Ultra Luxe hotel and casino. You meet him if you do the good karma version of the quest, “Beyond the Beef”. He is an evil, arrogant, and foul mouthed man.

The vanilla ways to deal with him are to use medicine or barter to get his recipes and cause him to leave, use speech to convince him to run into the pantry (you then lock him inside optionally you could pickpocket the recipes before doing this), sneak past once you got Ted Gunderson in your party, or just kill him and take the recipes.

I added two new main branches of dialogue for him. One is a method of getting recipes, and the other is a way to make a non lethal approach to getting him out of there easier.

First the recipes. First option towards getting the recipes is you trying to butter him up, saying you love his cooking, but first you need to convince him of that. In order to do so, you need to either be obese or morbidly obese (he’ll still be a prick, I tried my best to emulate his vanilla dialogue). If you aren’t, he won’t give you the time of day, but he does give a hint (as if it wasn’t obvious) to gain weight in his rejection dialogues. I made two rejection dialogues, one for normal-well fed and another for chubby-fat.

If you meet the weight level requirement, you can ask for the recipes for Brahmin Wellington, and for the recipe that’s helpful for getting the best outcome to Beyond the Beef. To get the Brahmin Wellington recipe, you need a speech of 40. To get the quest recipe, you need to know about what’s going on (from the meeting with Chauncey earlier in the quest) and either a speech of 45 or The Cannibal Perk.

The elimination method is based around the pantry. Go into the pantry and you will be given a message box with two options. Either try eating things in the pantry or walk away. There are two versions of eating in the pantry based on whether or not you have the Big Appetite trait. If you don’t have it, you only eat some of the pantry (gain +10 weight points). If you do have the trait, you eat everything (+30 weight points).

Once you’ve tried eating in the pantry, another option will appear for Philippe. The option allows you to tell him that you ate everything in the pantry. If you didn’t have the trait (and thus, this would be a lie since you didn’t eat everything), you need 30 speech and need to be obese or morbidly obese for him to check (there is dialogue for failing the check and just being too thin). If you had the trait, your weight level doesn’t matter for the outcome (though there is different dialouge depending on your weight). If you convince him, he will run into the pantry like if you passed the vanilla 55 speech check. Then you just lock him in like vanilla.

If what I’ve said is confusing, here is what you need to do to see what I did once I upload the demo:

-Talk to him while well fed or normal for rejection dialogue 1
-Talk to him while chubby or fat for rejection dialogue 2
-Be obese or morbidly obese to bring up the recipe dialogue
-have speech of 40 for the brahmin wellington recipe
-meet Chauncey during the good path of Beyond the Beef and have speech 45/Cannibal perk for the imitation recipe
-Go into the pantry yourself to unlock the elimination method
-the method requires you to have the trait, or be at least obese and 30 speech.


Damn, I’m such a huge NV fan.

Cant wait to see a playable version of this be released.


Trying to make a new quest using Vanilla NPCs. The first half of the quest line will be very simple (and perhaps a bit dull) since it’s my first quest. This again doesn’t edit vanilla quests.

The quest starts when you first eat Ruby Nash’s Casserole and if Ruby Nash (located in Primm) isn’t dead. The premise of the first half of the quest is to help her improve her cooking ability and the recipe. Once you agree to help sample her cooking, your current weight level is stored into a tracking variable that I will get back to later. First task is to eat 10 of her casseroles. This pretty much requires you hunt down 10 Radscorpion poison glands (Weight gained is +40 without the trait, and +60 if you have it). After you do this return to her for the second portion of the quest. The next part is to try 10 of her experimental new recipe that requires Bark Scorpion poison glands to make (Weight +50 without trait, Weight +80 with trait). Upon completion, you will receive 500XP, a determinate amount of caps, the ability to give her bark scorpion glands for the improved casserole, a total of 90 weight points gained without the trait or 140 weight if you have the trait (this came from eating the casseroles, not for completing the quest), and the next quest. If you are a higher weight level at the end of the quest vs the beginning you can complain and ask for more pay. If you are only 1 weight level higher you get some extra pay, if you are 2 you get quite a bit more, and if you are 3 or more you will not get anything because you get accused of being a glutton for other food as well (since it’s impossible to go up 3 weight levels by doing this quest alone).


It sounds like a pretty fun quest, especially for a Fallout game. And it works out pretty well because Primm is basically just a second tutorial town, so having a smaller quest makes sense.

Maybe another early quest could involve Trudy from Goodsprings? Like maybe you offer to lend a hand around town or maybe she’ll reward the player with some food after defending the town?


Pretty much got the first quest finished, just need to add some of the finishing touches to it. The second quest from Ruby Nash will be a bit more involved. The gist of it is that Ruby Nash will want to use the recipe to become a business partner with one of the various food vendors (and a couple other characters who do something else with the recipe) in the game. The difficulty and reward of the quest is dependent on who you decided to give the recipe to. You will get paid a cut every day in a trunk. The trunk will be in the Mojave Express building in Primm. You only get your cut if both Ruby Nash and whoever you sold the recipe to are alive. This will likely not have any quest markers and most of these NPCs won’t be mentioned by Ruby (I’ll probably only have her mention the Ultra Luxe since that is the most high pofile food vendor/restaurant in the game).

Characters that give you royalties on the recipe:
Trudy in Goodsprings (very easy, very low cap reward, Goodsprings fame)
Lacey in Mojave Outpost (average, low cap reward, moderage NCR fame)
Fitz at the Grub n’ Gulp (easy, low cap reward) (would recommend a mod that adds defenses to the grub n’ gulp because a legion hit squad spawns right next them if you have a low Legion rep. often killing Fitz)
Blake at the Crimson Caravan (average, moderate cap reward, low NCR fame)
Genaro in Freeside (very easy, low cap reward, freeside reputation change, quest solutions/failures)
Marjorie in the Ultra Luxe (Hard, high cap reward, strip fame, white glove society fame)

Characters that only give upfront rewards (essentially betraying what Ruby Nash asked of you):
Julie Farkas in Old Mormon Fort (Followers of the Apocalypse fame, Freeside fame)
William Farber in Camp Mcarran (NCR Reputation change, Upfront caps, potential for a handful of named NPCs around the camp to die)
Canyon Runner at Cottonwood Cove (Legion Reputation change, Upfront caps, potential for a handful of Legion soldiers to die around the camp)
Siri at the fort (Legion Reputation change, upfront legion money, potential for a handful of legion soldiers to die at the fort)

Note that if you give it to William Farber, Canyon Runner, or Siri and you chose not to tell them about the potential dangers of the casserole, you can ask Ruby Nash for another sample of the casserole to sell it to a different NPC. If you do warn these NPCs the quest will end and you’ll get either NCR or Legion fame instead of infamy.


I did some experimenting with the outfit studio. I made a couple sliders for the nude suits. I wasn’t happy with what I could make with the normal cbbe sliders, so I added a couple of rough sliders that I think really makes it look better. The change is most apparent for the higher weight levels.
Well fed:




Morbidly Obese:

What it used to look like at Morbid Obese: